tbuckley/cabot-search huggingface dataset:
IMMU-12. T CELL SEQUESTRATION IN POSTERIOR FOSSA TUMORS
Authors: Zach Wilson, Peter Fecci
Journal: Neuro-Oncology (2023)

Abstract INTRODUCTION T cell dysfunction contributes to immune escape in patients with cancer and is particularly severe in CNS tumors. T cell sequestration is a contributing mechanism of T cell lymphopenia and lymphoid organ contraction occurring in treatment naive patients and mice with Glioblastoma. Our group demonstrated that this phenomenon is mediated by loss of S1P1 surface expression on T-Cells within the bone marrow. We demonstrated in murine models that reversing T cell sequestration via stabilization of surface S1P1 licenses T cell activating therapies. As pediatric brain tumors much more commonly involve the posterior fossa and brainstem, the present work set out to assess whether T cell sequestration also occurs in tumors located in the cerebellum (medulloblastoma, high grade glioma). METHODS CT2A murine glioma cells were orthotopically implanted into the posterior fossa of C57BL/6 mice. Blood, spleen, and bone marrow were analyzed when tumors became sizable (Day 18-21). Flow cytometry was utilized to measure total, CD4+, and CD8+ T cell counts, as well as the proportion of T cells expressing surface S1P1. RESULTS Compared with mice injected with methylcellulose, mice bearing cerebellar CT2A tumors demonstrated significantly decreased splenic weight, increased total, CD4, and CD8 T cell counts in the bone marrow, and a decreased proportion of surface S1P1 expressing T cells within the bone marrow. CONCLUSIONS T cell sequestration within the bone marrow associated with loss of surface S1P1, as previously demonstrated in high grade tumors of the forebrain, also occurs with tumors implanted into the cerebellum, suggesting that the genesis T cell sequestration is independent of location within the brain. Future work on this project will add additional tumor histology to our analysis as well as measuring the effects of S1P1 stabilization on response to T cell activating therapies in these models of cerebellar tumors.
BIOL-16. OBESOGENIC DIET EXPOSURE INCREASES NF1-OPTIC PATHWAY GLIOMA FORMATION IN PART THROUGH EFFECTS ON THE CELL OF ORIGIN
Authors: Ambrose Chan, Kailong Zhang, Gemma Martin, David Gutmann, Nicole Brossier
Journal: Neuro-Oncology (2023)

Abstract Pediatric low-grade glioma incidence has been rising in the U.S. over the last 20 years, concurrent with a rising rate of obesity in both the adult and pediatric populations. Recently, children of obese mothers have been demonstrated to have increased rates of several tumors, including brain tumors. Importantly, obesity in the U.S. is driven in large part by diet, given the abundance and accessibility of high-fat, high-sugar food choices. High-fat diet exposure has been previously demonstrated to promote proliferation and glial differentiation of embryonic neuroglial progenitor cells (NPCs) around the third ventricular zone (TVZ), suggesting that in utero exposure to an obesogenic diet might affect the formation of pediatric tumors derived from these cells, such as Neurofibromatosis Type 1 (NF1)-related optic pathway glioma (OPG). Based on these data, we hypothesized that maternal obesogenic exposure would increase Nf1-OPG formation through intrinsic effects on the tumor cell of origin. We demonstrated that progeny from obese dams exposed to HFHS diet during and preceding gestation demonstrated increased proliferation and glial differentiation of WT and Nf1-heterozygous TVZ NPCs in vivo. Progeny of non-obese dams exposed to this diet during gestation demonstrated a similar phenotype, suggesting these effects were related to maternal diet rather than weight. We then assessed how obesogenic diet exposure affected tumor formation. We determined that this exposure increases glioma penetrance in two low-penetrance models of NF1-OPG. Finally, we demonstrated that obesogenic diet exposure resulted in earlier tumor onset in a high-penetrance Nf1-OPG model. Taken together, these findings suggest that obesogenic diet exposure increases pediatric glioma formation, in part through effects on the tumor cell of origin while still in utero. It may also have implications for clinical prognosis, as earlier age of tumor onset has been negatively associated with visual outcomes in NF1-OPG.
IMMU-13. PRECLINICAL EFFICACY OF MULTI-ANTIGEN (HER2/EGFR806/B7-H3/IL13RA2) TARGETING QUAD-CAR T CELLS AGAINST DIFFUSE MIDLINE GLIOMA
Authors: Carrie Myers, Andrea Timpanaro, Edward Song, Michael Meechan, Alex Chen, Matthew Biery, Aquene Reid, Kamila Gwiazda, Michael Baldwin, Joshua Gustafson, Rebecca Gardner, Michael Jensen, Nicholas Vitanza
Journal: Neuro-Oncology (2023)

Abstract BACKGROUND Diffuse midline glioma (DMG), including diffuse intrinsic pontine glioma (DIPG), remains a fatal disease. We have published the preclinical efficacy of HER2, EGFR806, and B7-H3 CAR-T cells and opened 3 trials (BrainChild-01, -02, and -03, respectively) that have delivered &amp;gt;350 intracranial CAR T doses to &amp;gt;70 enrolled children with recurrent/refractory CNS tumors and DIPG/DMG. While these trials have demonstrated the feasibility and tolerability of repeated, locoregional CAR-T cell dosing, responses have not been uniform in part due to tumor heterogeneity. METHODS Seattle Children’s Therapeutics generated multi-antigen (HER2, EGFR806, B7-H3, IL13ra2) quad-CAR T cells and we performed IND-enabling preclinical studies using CNS tumor models including DMG models (PBT-22, PBT-27, and PBT-29). RESULTS Quad-CAR T cells were generated by transducing T cells with a mixture of four vectors. The specificity of these CARs is conferred by scFv binding domains derived from the monoclonal antibodies Herceptin, mAb806, and MGA271 for HER2, EGFR806, and B7-H3, respectively. The IL13-zetakine, aligned with NCT00730613, carries an E13Y mutation in place of an scFv for specificity. In vitro, the quad-CAR T cells demonstrated significant in vitro cytolysis and cytokine (IL-2, IFNy, TNFa) production compared to mock (untransduced) CAR-Ts. In vivo, pilot studies in a GFP:ffLuc+Her2 U87 orthoptic xenograft mouse model showed significant survival (p&amp;lt;0.001). To validate against DMG, we are conducting a larger study of single dose intracranial quad-CAR T cells in an orthotopic xenograft PBT-29 DMG mouse model. While ongoing, at day 19 post-treatment there is already a significant bioluminescence decrease (p&amp;lt;0.001). In vivo studies will be completed and complimented by tumor spatial transcriptomics. CONCLUSION Quad-CAR T cell targeting of DMG is highly effective preclinically. A phase I trial of repeated, locoregional quad-CAR T cells for children with recurrent/refractory CNS tumors and DIPG/DMG is FDA-approved and will open in 2023.
MDB-35. RECURRENT MEDULLOBLASTOMA A RARE COMPLETE RESPONSE IN EXTRA NEURAL DISEASE
Authors: Jonathan Schwartz, Dena Weinmann, Heather Johnson, Khatua Soumen, Bryan Neth, Gesina Keating
Journal: Neuro-Oncology (2023)

Abstract Extra-neural metastasis in recurrent medulloblastoma, carries a potentially fatal outcome. No robust salvageable therapeutic strategy is present, for these clinical phenotypes. We present an 18-year male, who presented at the age of 8 years as a standard risk medulloblastoma and was treated with chemotherapy (as per ACNS0331) followed by craniospinal radiation. At first recurrence in the thoracic spine, he underwent a gross total resection of the tumor, followed by high-dose stem cell chemotherapy and focal radiation. The 2nd recurrence which occurred in the thecal sac 9 years later was treated with metronomic anti angiogenic chemotherapy with outcome a complete radiographic response. Third recurrence occurred in the liver, bone marrow, multiple bones of axial skeleton and sacrum. Molecular interrogation of the lesions showed a (non-WNT / non-SHH subtype) with absence of MYC or MYCN amplification or any other clinically significant biological aberration. He received local radiation to tumors, following which he developed severe myelosuppression. A bone marrow aspirate and biopsy showed greater than 95% involvement with medulloblastoma cells. He was treated with irinotecan and temozolomide. A dramatic response was noted after one cycle (with PET and MRI), with bone marrow involvement of less than 1%. He continues with that therapy. To-date no defined molecular profile is predictive of extra neural metastasis, and has been likened to a fatal outcome, most patients being declared for hospice care. Our patient with this unique clinical outcome, warrants extensive evaluation of these rare clinical phenotypes including methylation profiling and RNA sequencing, which might suggest, certain molecular aberrations which correlates with good response, even in these biologically aggressive variants.
DIPG-44. DIFFUSE MIDLINE GLIOMA WITH EXTRACRANIAL METASTASIS
Authors: Alexandra Giantini Larsen, Maricruz Rivera, David Pisapia, Sameer Farouk Sait, Matthias Karajannis, Jeffrey Greenfield, Mark Souweidane
Journal: Neuro-Oncology (2023)

Abstract Diffuse midline gliomas (DMGs) are malignant infiltrative gliomas enriched in the pediatric population and characterized by loss of the H3 K27me3 epigenetic marker, most frequently via mutation of the H3F3A gene. Few cases of extracranial DMG metastasis with redemonstrated H3F3A p.K28M (K27M) mutation in metastatic tissue are reported in the literature. Here, we report two such patients, both females (ages 12 and 15), with DMG and extracranial metastasis who died 5 years after initial diagnosis. The first patient with thalamic DMG underwent biopsy, radiation, chemotherapy, and subsequent decompression of spinal metastasis. Initial tumor biopsy demonstrated mutation in BRAF p.V600E, H3F3A K27M, and TERT promoter. The epidural spinal metastasis had mutations in BRAF p.V600E, H3F3A, TERT, and TP53. The second patient with brainstem DMG, diagnosed by radiographic appearance, underwent conventional external beam radiation therapy, chemotherapy including panobinostat and direct delivery of radioimmunotherapy, intra-arterial delivery of bevacizumab, and subsequent decompression of spinal metastasis. The histology and molecular profile for the spinal metastasis was consistent with DMG H3 K27M-mutant, with mutations in BRAF p.G464V, PTPN11 p.R498L, PDGFRA, and KIT. Bone marrow biopsy demonstrated atypical extrinsic cells with strong and diffuse immunolabeling for OLIG2. Autopsy revealed solid organ and osseous metastases. Both patients significantly exceeded the median life expectancy for DMG, raising the possibility that prolonged overall survival permitted progression to a rarely observed disseminated state of disease. There was absence of TP53/p53 modulating pathway mutation seen in classic DMG in the thalamic biopsy of the first patient, as well as the metastatic disease for the second patient, which may contribute to the prolonged survival observed. Molecular analysis of metastatic disease is important, as clinically and prognostically relevant alterations that vary from the primary site of disease may be detected, which shed light on clonal evolution patterns and further our understanding of disease biology.
DIPG-24. BRD4 INHIBITION AS A RADIOSENSITIZER THROUGH BLOCKING DNA REPAIR FOR THE TREATMENT OF DIFFUSE MIDLINE GLIOMA
Authors: Jun Watanabe, Matt Clutter, Christine Hoeman, Sui Amreena, Koki Abe, Yukitomo Ishi, Eita Uchida, Oren Becker, Rintaro Hashizume
Journal: Neuro-Oncology (2023)

Abstract Diffuse intrinsic pontine glioma (DIPG) is one of the devastating childhood cancers. Radiation therapy (RT) remains the only effective treatment yet provides a 5-year survival rate of only 1%. Several clinical trials have attempted to enhance RT efficacy by combining it with radiosensitizing agents, though none have been successful in doing so. Given this, there is a critical need to identify effective therapeutics to enhance the RT anti-tumor activity in DIPG. Here, we identified BRD4 inhibitors as candidate radiosensitizers from a high throughput drug screening. DIPG cells show increased H3 K27 acetylation (H3K27ac) levels, which bind to BET bromodomain protein 4 (BRD4) and are strongly associated with active transcription. We tested two BRD4 inhibitors (BRD4i: AZD5153 and JQ-1) as well as genetic BRD4 depletion, and observed enhancement of radiation-induced DNA damage, confirming BRD4i as potential radiosensitizers in the treatment of DIPG. We evaluated the effects of BRD4i on gene expression using RNAseq, and observed significant inhibition of DNA-repair proteins such as BRCA1 and RAD51. CUT-RUN qPCR showed decreased H3K27ac at BRCA1 and RAD51 promoters. Combination of BRD4i and RT inhibited cell viability significantly using clonogenic survival assay, apoptosis assay, and also showed cell cycle arrest. Radiation-induced DNA double-strand break (DSB) repair was prolonged with BRD4i with high levels of gH2AX and 53BP1 likely due to inhibition of DNA-repair. In vivo studies revealed increased survival of animals treated with combination therapy of RT and BRD4i in comparison to either monotherapy. Together, these results highlight BRD4i as a potential radiosensitizer and provide a rationale for developing combination therapy with radiation in the treatment of DIPG.
EPEN-05. TRANSCRIPTIONAL FACTOR-DIRECTED EPIGENETIC REGULATION IN CANCER NEUROSCIENCE OF ZFTA-RELA EPENDYMOMA
Authors: Hsiao-Chi Chen, Malcolm McDonald, Srinidhi Varadharajan, Debosmita Sardar, Stephen C Mack, Benjamin Deneen
Journal: Neuro-Oncology (2023)

Abstract ZFTA-RELA (ZRFUS) ependymoma is a pediatric brain tumor with dismal 10-year progression free survival rates. Prior studies revealed low somatic mutation load in pediatric ependymoma compared to adult glioma, suggesting that developmental mechanisms play a key role during disease development. Using human tissues and mouse tumors generated from our autochthonous in utero electroporation (IUE) model, we identified a cohort of developmental transcription factors (TFs) linked to ZRFUS by investigating histone serotonylation changes with other epigenetic datasets. We further performed in vivo barcode-screening and identified the ETS variant transcription factor 5 (ETV5) is sufficient and required for disease progression. To further reveal the disease mechanism driven by ETV5, we applied transcriptomic, epigenetic, and proteomic analyses, and found ETV5 suppresses neuropeptide Y (NPY) expression in mouse ZRFUS tumors by binding with epigenetic modulator, chromobox 3 (CBX3). We further found NPY overexpression delays tumor progression and suppressed tumor-driven neuronal activity in mice. This study suggests developmental TF can shape tumor-promoting microenvironment during disease progression through epigenetic regulation.
Anal Carcinoma, Version 2.2023, NCCN Clinical Practice Guidelines in Oncology
Authors: Al B. Benson, Alan P. Venook, Mahmoud M. Al-Hawary, Nilofer Azad, Yi-Jen Chen, Kristen K. Ciombor, Stacey Cohen, Harry S. Cooper, Dustin Deming, Ignacio Garrido-Laguna, Jean L. Grem, J. Randolph Hecht, Sarah Hoffe, Joleen Hubbard, Steven Hunt, Hisham Hussan, William Jeck, Kimberly L. Johung, Nora Joseph, Natalie Kirilcuk, Smitha Krishnamurthi, Jennifer Maratt, Wells A. Messersmith, Jeffrey Meyerhardt, Eric D. Miller, Mary F. Mulcahy, Steven Nurkin, Michael J. Overman, Aparna Parikh, Hitendra Patel, Katrina Pedersen, Leonard Saltz, Charles Schneider, David Shibata, John M. Skibber, Constantinos T. Sofocleous, Eden Stotsky-Himelfarb, Anna Tavakkoli, Christopher G. Willett, Grant Williams, Frankie Algieri, Lisa Gurski, Katie Stehman
Journal: Journal of the National Comprehensive Cancer Network (2023)

This discussion summarizes the NCCN Clinical Practice Guidelines for managing squamous cell anal carcinoma, which represents the most common histologic form of the disease. A multidisciplinary approach including physicians from gastroenterology, medical oncology, surgical oncology, radiation oncology, and radiology is necessary. Primary treatment of perianal cancer and anal canal cancer are similar and include chemoradiation in most cases. Follow-up clinical evaluations are recommended for all patients with anal carcinoma because additional curative-intent treatment is possible. Biopsy-proven evidence of locally recurrent or persistent disease after primary treatment may require surgical treatment. Systemic therapy is generally recommended for extrapelvic metastatic disease. Recent updates to the NCCN Guidelines for Anal Carcinoma include staging classification updates based on the 9th edition of the AJCC Staging System and updates to the systemic therapy recommendations based on new data that better define optimal treatment of patients with metastatic anal carcinoma.
MDB-19. MULTIOMIC PROFILING OF MEDULLOBLASTOMA REVEALS SUBTYPE-SPECIFIC TARGETABLE ALTERATIONS AT THE PROTEOME AND N-GLYCAN LEVEL
Authors: Shweta Godbole, Hannah Voss, Simon Schlumbohm, Yannis Schumann, Bojia Peng, Martin Mynarek, Stefan Rutkowski, Matthias Dottermusch, Mario M Dorostkar, Andrey Koshunov, Thomas Mair, Stefan M Pfister, Philipp Neumann, Christian Hartmann, Joachim Weis, Friederike Liesche-Starnecker, Yudong Guan, Hartmut Schlüter, Ulrich Schüller, Christoph Krisp, Julia E Neumann
Journal: Neuro-Oncology (2023)

Abstract Medulloblastomas (MBs) are malignant pediatric brain tumors which are clinically and histologically very heterogeneous. Epigenomic and transcriptomic analyses have advanced the understanding of these tumors and four main molecular subgroups – which themselves comprise several subtypes- have been defined: WNT-activated MB, Sonic hedgehog (SHH)-activated MB, Group3 and Group4 MB. Despite tremendous advances in classification and stratification, the pathogenesis of subtypes is still poorly understood and there is still a lack of targeted therapies. In contrast to nucleic acids, proteins more directly account for the phenotype and hold the potential to discover clinically relevant phenotypes, new biomarkers and therapy targets. In this study, we put together a harmonized cohort of 167 MB samples and integrated proteome data with DNA methylome and N-glycan data. At proteome level, we found six stable subtypes which could be assigned to two main molecular signatures namely-transcriptional/translational processes (pWNT, pG3myc and pSHHt) and synaptic/immunological processes (pG3, pG4 and pSHHs). pG3myc MB showed poor survival and accumulated high risk features such as anaplastic histology, epigenetic subtype II and MYC amplification. They showed an overlap of proteome patterns with favorable pWNT MBs but displayed significantly different protein abundancies of the vincristine resistance associated TriC/CCT complex and N-glycan turnover associated factors. Of note. N-glycan profiles distinguished MB subtypes and pG3myc MBs were enriched by complex bisecting N-glycans. We further identified Tenascin C (TNC) and Palmdelphin (PALMD) as suitable biomarkers for the pWNT and pG3myc MBs, respectively. Integration of proteome and DNA methylome data revealed that pWNT MBs showed the highest correlation of data modalities among MB subtypes, indicating a higher conservation of biological processes compared to other proteome subtypes. Our results shed light on new targetable alterations in MB and set a foundation for potential immunotherapies targeting glycan structures.
IMG-04. POTENTIAL TARGETS FOR THERANOSTICS IN PEDIATRIC HIGH-GRADE CENTRAL NERVOUS SYSTEM (CNS) TUMORS
Authors: Sabine Plasschaert, Nelleke Tolboom, Lennart Kester, Bastiaan Tops, Eelco Hoving, Alex Poot, Pieter Wesseling, Mariëtte Kranendonk
Journal: Neuro-Oncology (2023)

Abstract Theranostics refers to the combination of a radioactive drug to identify (diagnose) and another radioactive drug to deliver therapy to cancer. In adult cancer several radiopharmaceuticals with specificity for receptors like cx-chemokine-receptor type 4 (CXCR-4), prostate-membrane specific antigen (PSMA), and somatostatine receptor (SSTR2a) are used. Especially PSMA for prostate cancer and SSTR2a ligands for neuro-endocrine tumors have proven their value. Moreover, novel promising targets like B7-H3 are upcoming. In children the potential of such theranostic drugs have been minimally explored. AIM of this study is to explore the expression of theranostic markers CXCR-4, PSMA, SSTR2a and B7-H3 in a broad cohort of high-grade pediatric CNS tumors to determine the potential of these imaging ligands in this cohort. METHODS The expression of CXCR-4, PSMA, SSTR2a and B7-H3 were examined both by RNA (by bulk RNAsequencing) and protein level (by immunohistochemistry (IHC)) (RNA n=161/IHC n=52) in pediatric high-grade CNS tumors: ependymomas (n=33/11), atypical teratoid rhabdoid tumors (ATRT) (n=9/7), medulloblastomas (n=51/11), diffuse midline gliomas H3K27-altered (n=27/9) and other high-grade gliomas (n=41/15). RESULTS mRNA expression of CXCR-4 was present but low in most tumor types, with the highest expression in medulloblastoma. Immunohistochemistry showed variable CXCR-4 expression, with the highest expression in some medulloblastomas, ependymomas and ATRTs. PSMA (FOLH1) mRNA and protein expression was generally very low. As expected SSTR2a showed a very high mRNA and protein expression only in medulloblastoma samples. Remarkably, B7-H3 (CD276) showed a relatively high expression in all high-grade pediatric CNS tumor types, both on RNA and protein level. CONCLUSION Of the four potential theranostic targets tested, SSTR2a is an interesting antigen in medulloblastoma. CXCR-4 could be of interest for individual patients with medulloblastoma, ATRT or ependymoma. Finally, B7-H3 is widely but variably expressed on all different tumor types, and seems a promising novel target for theranostics in pediatric CNS tumors.
DIPG-02. A NOVEL STRATEGY TO RADIOSENSITISE DIFFUSE MIDLINE GLIOMAS VIA DUAL-TARGETING OF GLUCOSE METABOLISM
Authors: Han Shen, Cecilia Chang, Prunella Ing, Sandy Nguyen, Faiqa Mudassar, Kristina Cook, Joey Lai, Brian Gloss, Geraldine O’Neill, Harriet Gee, Eric Hau
Journal: Neuro-Oncology (2023)

Abstract Diffuse Midline Gliomas (DMG) is the leading cause of brain tumor-related death in children. Currently, radiation is the only treatment that offers transient benefit but almost all DMG relapse due to radioresistance. Compared to normal brain tissue, DMG are hypo-perfused with tumor cells being exposed to hypoxia, a low oxygen microenvironment serves as a potent barrier to effective radiotherapy. Biguanides are hypoglycemic agents that can reduce the oxygen consumption rate (OCR) in mitochondria, thereby sparing more oxygen and alleviating hypoxia. Our previous study has shown that metformin significantly improves the radiosensitivity of DMG and extends survival in a patient-derived xenograft (PDX) model. In comparison with metformin, phenformin demonstrated greater efficacies in anti-proliferation, OCR and hypoxia inhibition, and radiosensitization in a panel of DMG cultures. These effects were possibly induced by phenformin through inhibition of mitochondrial complex I in DMG cells. The anti-tumor effect of phenformin was further enhanced by combining a second drug dichloroacetate that simultaneously attenuated phenformin-induced acidification. Specifically, the combination treatment induced higher levels of reactive oxygen species and DNA damage, which subsequently resulted in a much stronger effect in cell-cycle and proliferation arrest, apoptosis, and hypoxia inhibition. Metabolically, the co-treatment simultaneously targeted multiple pathways, which significantly reduced ATP production and further triggered metabolic catastrophe. RNA sequencing demonstrated significant alterations induced by the combination in cell-cycle, DNA repair, unfolded protein response and alternative energetic pathways. Furthermore, the combination treatment significantly improved the radiosensitivity of DMG cells, evidenced by higher levels of DNA damage, apoptosis, and clonogenic inhibition. Our preliminary in vivo data demonstrated a possible reduction in tumor burden following 4 weeks of combination treatment, with no elevation of serum L-lactate level in phenformin-treated groups. This therapeutic efficacy is currently being validated in multiple orthotopic DMG models with optimized treatment schedules.